Epoxy Resin

[Namery]

Help!
Can anyone give me a few pointers on applying epoxy resin to my Dumas Chris Craft model #1249?
If you could advise brand and best application method I would appreciate it.
I’m after a glass, high gloss finish.
Many thanks!

 

[Graham]

Are you talking about applying resin as a coating on the hull?

 

[Namery]

Hi Graham,
Thx for getting back to me.
Yes, each and hull.
I’m after the high gloss, glass finish and know there’s a lot of sanding and coating involved!
Just want some advice!
Appreciate your help!

 

[Bob Cleek]

Hi Graham,
Thx for getting back to me.
Yes, each and hull.
I’m after the high gloss, glass finish and know there’s a lot of sanding and coating involved!
Just want some advice!
Appreciate your help!

Advice? Don't do it. What's the reason you want to do this? If it's to get a glossy finish (which will make the model look like a toy,) then you're best bet is multiple coats of spar varnish. Clear epoxy resin is very difficult to finish to a high gloss.

If you are looking for reinforcement to increase strength or resist abrasion, I would not advise using epoxy resin alone. Rather, the resin should be used as the binding agent in a resin and glass cloth composite lamination.

Epoxy resin is very susceptible to UV degradation. Any epoxy resin should be overcoated with varnish containing UV inhibitors or opaque paint.

The most respected brand of epoxy resins and products is WEST System. Their extensive instruction manual is online at https://www.westsystem.com/instruction/user-manual-product-guide/ The WEST user's manual have everything you could possibly want to know about the use of epoxy resins.

 

[Namery]

Many, many thanks Graham.
Have to say the gloss varnish is something I’m more used to, having done full size sailing yachts in my years. Just not models before.
I’m leaning towards what I know and more familiar with… so thanks! I think you’ve just made my mind up.
Best get my sanding head on!

 

[AndyA]

Many, many thanks Graham.
Have to say the gloss varnish is something I’m more used to, having done full size sailing yachts in my years. Just not models before.
I’m leaning towards what I know and more familiar with… so thanks! I think you’ve just made my mind up.
Best get my sanding head on!

Like so many things, it depends. First, is it a display model or a RC model? If for display only, no epoxy is needed. If it's going to go in the water, epoxy with fiberglass cloth (as Cap'n Cleek suggests) makes for a sturdy and stable hull. As far as high gloss varnish, Cap'n Cleek is right again; it makes a model look like a toy. The difference is one of scale. A full size craft with a new, shiny coat of varnish looks beautiful from a few feet away. At any distance, the gloss cannot be seen in the same way. To be realistic looking, a model should be painted (or varnished) to look like the real thing at a distance. If you look at a model of 1:100 scale from 1 foot away, your brain sees it as a full size vessel at 100 feet. Landscape painters have understood this for centuries. Folks who build model aircraft haven't understood this for that long, but they have explored the phenomenon. Bottom line: a satin finish would look more realistic. Fair winds!

 

[Namery]

Thank you AndyA.
Varnish it will be!

 

[Bob Cleek]

If you varnish, I would suggest that you do not use "satin" varnish. "Satin" varnish, as described on the can, is only regular varnish with a flattening agent added. The flattening agent is usually ground silica, which disperses the light reflected from the varnish. The problem is that unless the flattening agent is well distributed in suspension in the varnish, the level of flattening in the finished product will not be evenly distributed. Indeed, a common complaint from those unfamiliar with the product is that they applied it and the dried varnish is indistinguishable from gloss varnish! This occurs when someone applies "satin varnish" directly from the top of the can without stirring it at all.

The second issue with "satin" varnishes is that they have little or no ultraviolet shielding material added to mitigate UV damage from sunlight. UV protection is essential for any varnish that will be exposed to direct sunlight for any significant amount of time. A model should never be left exposed to direct sunlight, of course, but, nevertheless, standard marine spar varnish with UV shielding is a much more archival material than "satin" varnish, so it's better to use it where possible.

The way a "real" satin finish is obtained on a varnished surface is by applying gloss varnish, allowing it to dry and cure well (a few days) and then rub it with a fine abrasive powder. (As I expect you know, several coats of varnish should be built up to create some depth to the finish.) The classic abrasives are pumice and rottenstone. Pumice is the coarser of the two. They are fine powders that are applied to a soft, damp cloth that is used to hand rub the surface. Pumice will remove the gloss easily. Rottenstone is so fine that it will actually create a gloss finish again if rubbed enough. They produce an incredibly smooth surface. Whether one uses "satin" varnish or regular gloss varnish, the finish is initially dependent upon the care taken in its application, whether by brush or spray. Regardless of which, however, the finish will have imperfections, however minor, such as the occasional speck of dust. Hand rubbing removes all of these minute imperfections and creates a perfect "fine furniture" finish. Nothing detracts from the impression of reality in a model more than an imperfect finishing job. Hand rubbing is the only way to obtain that perfection. This is how all the finest ship models in the major maritime museums were finished, whether they were painted or varnished. Of course, hand rubbing is only really possible on smooth surfaces. If you have a hull full of port lights or other detail, any hand rubbing would have to be done before the "bumpy" detail is added.

An alternate approach to using pumice and rottenstone is the use of a fine Scotchbrite pad. The pad is used in the same fashion as the soft cloth and abrasive powders. Pumice and Rottenstone, as well as fine Scotchbrite pads should be available in any paint store and are relatively inexpensive..

 

[Namery]

If you varnish, I would suggest that you do not use "satin" varnish. "Satin" varnish, as described on the can, is only regular varnish with a flattening agent added. The flattening agent is usually ground silica, which disperses the light reflected from the varnish. The problem is that unless the flattening agent is well distributed in suspension in the varnish, the level of flattening in the finished product will not be evenly distributed. Indeed, a common complaint from those unfamiliar with the product is that they applied it and the dried varnish is indistinguishable from gloss varnish! This occurs when someone applies "satin varnish" directly from the top of the can without stirring it at all.

The second issue with "satin" varnishes is that they have little or no ultraviolet shielding material added to mitigate UV damage from sunlight. UV protection is essential for any varnish that will be exposed to direct sunlight for any significant amount of time. A model should never be left exposed to direct sunlight, of course, but, nevertheless, standard marine spar varnish with UV shielding is a much more archival material than "satin" varnish, so it's better to use it where possible.

The way a "real" satin finish is obtained on a varnished surface is by applying gloss varnish, allowing it to dry and cure well (a few days) and then rub it with a fine abrasive powder. (As I expect you know, several coats of varnish should be built up to create some depth to the finish.) The classic abrasives are pumice and rottenstone. Pumice is the coarser of the two. They are fine powders that are applied to a soft, damp cloth that is used to hand rub the surface. Pumice will remove the gloss easily. Rottenstone is so fine that it will actually create a gloss finish again if rubbed enough. They produce an incredibly smooth surface. Whether one uses "satin" varnish or regular gloss varnish, the finish is initially dependent upon the care taken in its application, whether by brush or spray. Regardless of which, however, the finish will have imperfections, however minor, such as the occasional speck of dust. Hand rubbing removes all of these minute imperfections and creates a perfect "fine furniture" finish. Nothing detracts from the impression of reality in a model more than an imperfect finishing job. Hand rubbing is the only way to obtain that perfection. This is how all the finest ship models in the major maritime museums were finished, whether they were painted or varnished. Of course, hand rubbing is only really possible on smooth surfaces. If you have a hull full of port lights or other detail, any hand rubbing would have to be done before the "bumpy" detail is added.

An alternate approach to using pumice and rottenstone is the use of a fine Scotchbrite pad. The pad is used in the same fashion as the soft cloth and abrasive powders. Pumice and Rottenstone, as well as fine Scotchbrite pads should be available in any paint store and are relatively inexpensive..

If you varnish, I would suggest that you do not use "satin" varnish. "Satin" varnish, as described on the can, is only regular varnish with a flattening agent added. The flattening agent is usually ground silica, which disperses the light reflected from the varnish. The problem is that unless the flattening agent is well distributed in suspension in the varnish, the level of flattening in the finished product will not be evenly distributed. Indeed, a common complaint from those unfamiliar with the product is that they applied it and the dried varnish is indistinguishable from gloss varnish! This occurs when someone applies "satin varnish" directly from the top of the can without stirring it at all.

The second issue with "satin" varnishes is that they have little or no ultraviolet shielding material added to mitigate UV damage from sunlight. UV protection is essential for any varnish that will be exposed to direct sunlight for any significant amount of time. A model should never be left exposed to direct sunlight, of course, but, nevertheless, standard marine spar varnish with UV shielding is a much more archival material than "satin" varnish, so it's better to use it where possible.

The way a "real" satin finish is obtained on a varnished surface is by applying gloss varnish, allowing it to dry and cure well (a few days) and then rub it with a fine abrasive powder. (As I expect you know, several coats of varnish should be built up to create some depth to the finish.) The classic abrasives are pumice and rottenstone. Pumice is the coarser of the two. They are fine powders that are applied to a soft, damp cloth that is used to hand rub the surface. Pumice will remove the gloss easily. Rottenstone is so fine that it will actually create a gloss finish again if rubbed enough. They produce an incredibly smooth surface. Whether one uses "satin" varnish or regular gloss varnish, the finish is initially dependent upon the care taken in its application, whether by brush or spray. Regardless of which, however, the finish will have imperfections, however minor, such as the occasional speck of dust. Hand rubbing removes all of these minute imperfections and creates a perfect "fine furniture" finish. Nothing detracts from the impression of reality in a model more than an imperfect finishing job. Hand rubbing is the only way to obtain that perfection. This is how all the finest ship models in the major maritime museums were finished, whether they were painted or varnished. Of course, hand rubbing is only really possible on smooth surfaces. If you have a hull full of port lights or other detail, any hand rubbing would have to be done before the "bumpy" detail is added.

An alternate approach to using pumice and rottenstone is the use of a fine Scotchbrite pad. The pad is used in the same fashion as the soft cloth and abrasive powders. Pumice and Rottenstone, as well as fine Scotchbrite pads should be available in any paint store and are relatively inexpensive..

Many thanks Bob.
I think I’m going to go with the Spar varnish and really take my time on the sanding and coating.
Many coats!
Much rubbing down.
Appreciate your advice.
Thank you.